Thermal harvesting for vehicle brakes
A system including a magnet configured to move in response to a movement of a wear pin indicator of a brake assembly of a vehicle. A sensor is configured to generate position data corresponding to the magnet. The position data is indicative of a position and/or movement of the wear pin indicator. The system includes a thermoelectric generator configured to generate an electrical signal based on an operation of the brake assembly. The thermoelectric generator is configured to deliver at least a portion of the electrical signal to the sensor. The system includes a mounting bracket configured to mechanically couple a sensor housing to an actuator housing of the brake assembly. The mounting bracket is configured to provide heat to the thermoelectric generator when the mounting bracket mechanically couples the sensor housing and the actuator housing.
1 . A system, comprising:
a sensing device including:
sensing circuitry configured to generate position data corresponding to movement of a wear pin indicator configured to indicate translation of a disc stack of a brake assembly relative to an actuator housing of the brake assembly, and wherein the sensing circuitry is configured to generate the position data using electrical power, and
conditioning circuitry configured to provide the electrical power to the sensing circuitry;
a thermoelectric generator configured to provide the electrical power to the conditioning circuitry, wherein the thermoelectric generator defines a hot node and a cold node, and wherein the thermoelectric generator is configured to produce the electrical power based on a temperature gradient between the hot node and the cold node, wherein the thermoelectric generator includes a solid-state device having a thermoelectric sensitivity sufficient to cause the solid-state device to develop a device voltage greater than a cutoff voltage;
shunt circuitry, wherein the thermoelectric generator is configured to produce the electrical power at a thermoelectric generator voltage (TEG voltage), and wherein the shunt circuitry is configured to limit a voltage of the electrical power provided to the conditioning circuitry to less than or equal to the cutoff voltage when the TEG voltage exceeds the cutoff voltage;
a heat sink configured to transfer heat from the cold node to an environment surrounding the brake assembly;
a sensor housing mechanically supporting at least the sensing device, the thermoelectric generator, and the heat sink; and
a mounting bracket mechanically coupled to the sensor housing, wherein the mounting bracket is configured to attach to the actuator housing, and wherein the mounting bracket is configured to transfer heat from the actuator housing to the hot node to generate the temperature gradient when the mounting bracket is attached to the actuator housing.
2 . The system of claim 1 , further comprising communication circuitry mechanically supported by the sensor housing, wherein the communication circuitry is configured to transmit the position data to an external device using the electrical power produced by the thermoelectric generator.
3 . The system of claim 1 , wherein the mounting bracket is configured to displace the sensor housing from the actuator housing when the mounting bracket is attached to the actuator housing.
4 . The system of claim 1 , wherein the mounting bracket is configured to position the sensor housing substantially between the actuator housing and a pressure plate of the brake assembly when the mounting bracket is attached to the actuator housing.
5 . The system of claim 1 , wherein the mounting bracket is configured to transfer heat by conduction from the actuator housing to the hot node when the mounting bracket is attached to the actuator housing.
6 . The system of claim 1 , wherein the sensing device is configured to generate the position data when a wear pin extends through the sensor housing, and wherein the position data corresponds to movement of the wear pin.
7 . The system of claim 1 ,
wherein the mounting bracket is configured to attach to the actuator housing of the brake assembly when the brake assembly provides braking of a wheel of a vehicle moving in a direction of travel,
wherein the heat sink includes a base and a plurality of fins extending from the base, and
wherein the sensor housing mechanically supports the heat sink such that the fins extend from the base in a direction substantially parallel to the direction of travel when the mounting bracket is attached to the actuator housing.
8 . The system of claim 1 , wherein the heat sink comprises a plurality of members defining a mesh, wherein the plurality of members are configured to transfer the heat from the hot node to the environment surrounding the brake assembly.
9 . The system of claim 1 , wherein the shunt circuitry is configured to limit the voltage of the electrical power provided to the conditioning circuit when the temperature gradient generated by the heat transfer of the mounting bracket exceeds a temperature gradient threshold.
10 . The system of claim 1 , wherein the shunt circuitry includes a diode configured to shunt a portion of the electrical power produced by the thermoelectric generator to a common electrical node of the system when the TEG voltage exceeds a forward bias voltage of the diode.
11 . The system of claim 1 , wherein the shunt circuitry includes a field-effect transistor configured to shunt a portion of the electrical power produced by the thermoelectric generator to a common electrical node of the system, wherein the portion of the electrical power shunted is based on a gate voltage of the field-effect transistor, and wherein the gate voltage is based on the TEG voltage.
12 . The system of claim 1 , wherein the shunt circuitry is configured to adjust a stepping ratio of a tapped transformer configured to receive at least a part of the electrical power produced by the thermoelectric generator and provide the part of the electrical power to the conditioning circuitry.
13 . The system of claim 1 , further comprising:
the braking assembly, wherein the braking assembly includes a piston configured to move relative to the actuator housing to cause the translation of the disc stack relative to the actuator housing; and
the wear pin indicator, wherein the wear pin indicator is configured to indicate translation of the disc stack relative to the actuator housing.
14 . A system, comprising:
a thermoelectric generator configured to provide electrical power to conditioning circuitry of the system, the conditioning circuitry configured to receive at least some portion of the electrical power from the thermoelectric generator, wherein the thermoelectric generator defines a hot node and a cold node, wherein the thermoelectric generator is configured to produce the electrical power based on a temperature gradient between the hot node and the cold node, wherein the thermoelectric generator is configured to produce the electrical power at a thermoelectric generator voltage (TEG voltage);
shunt circuitry; wherein the shunt circuitry includes a diode configured to shunt a portion of the electrical power produced by the thermoelectric generator to a common electrical node of the system when the TEG voltage exceeds a forward bias voltage of the diode, and wherein the shunt circuitry is configured to limit a voltage of the electrical power provided to the conditioning circuitry to less than or equal to a cutoff voltage when the TEG voltage exceeds the cutoff voltage;
a heat sink configured to transfer heat from the cold node to an environment surrounding a brake assembly;
a sensor housing mechanically supporting at least the thermoelectric generator and the heat sink; and
a mounting bracket mechanically coupled to the sensor housing,
wherein the mounting bracket is configured to attach to an actuator housing of the brake assembly,
wherein the mounting bracket is configured to displace the sensor housing from the actuator housing when the mounting bracket is attached to the actuator housing,
wherein the mounting bracket is configured to position the sensor housing substantially between the actuator housing and a pressure plate of the brake assembly when the mounting bracket is attached to the actuator housing, and
wherein the mounting bracket is configured to transfer heat by conduction from the actuator housing to the hot node to generate the temperature gradient when the mounting bracket is attached to the actuator housing.
15 . The system of claim 14 , further comprising:
sensing circuitry configured to generate position data corresponding to movement of a wear pin indicator configured to indicate translation of a disc stack of the brake assembly relative to the actuator housing, wherein the sensing circuitry is configured to generate the position data using the electrical power; and
communication circuitry mechanically supported by the sensor housing, wherein the communication circuitry is configured to transmit the position data to an external device using the electrical power produced by the thermoelectric generator.
16 . A method, comprising:
providing electrical power, using a thermoelectric generator, to a sensing device, wherein the thermoelectric generator defines a hot node and a cold node, and wherein the thermoelectric generator produces the electrical power based on a temperature gradient between the hot node and the cold node, and wherein the thermoelectric generator is configured to produce the electrical power at a thermoelectric generator voltage (TEG voltage);
limiting a voltage of the electrical power provided to conditioning circuitry to less than or equal to a cutoff voltage when the TEG voltage exceeds the cutoff voltage using shunt circuitry;
generating, using the sensing device, position data corresponding to movement of a wear pin indicator configured to indicate translation of a disc stack of a brake assembly relative to an actuator housing of the brake assembly, wherein the sensing device generates the position data using the electrical power;
transferring heat, using a mounting bracket mechanically coupled to the actuator housing, from the actuator housing to the hot node to generate the temperature gradient, wherein the mounting bracket is mechanically coupled to a sensor housing mechanically supporting at least the sensing device, the thermoelectric generator, and a heat sink; and
transferring heat, using the heat sink, from the cold node to an environment surrounding the brake assembly.
17 . The method of claim 16 , further comprising transmitting, using communication circuitry mechanically supported by the sensor housing, the position data to an external device, wherein the communication circuitry transmits the position data using the electrical power produced by the thermoelectric device.